In 2015, my family and I decided to build a home greenhouse to expand our gardening options and growing season. The greenhouse we chose was a 20’x10′ unit wade with 10mm double wall polycarbonate wall and roof panels. We thought that the frame would be rigid enough that our greenhouse foundation could be a simple heavy wooden frame on the ground (most greenhouse kits recommend either railroad ties or a poured concrete foundation).
Unfortunately, that didn’t work out so well. Given the size of the greenhouse, no matter how carefully we tried to level the frame, we still couldn’t get it completely square along the entire length. I didn’t want to sacrifice the ability to plant straight in the dirt inside the greenhouse, and whatever we built had to stay level during the course of yearly freeze and thaw cycles here in Wisconsin. We had to think outside the box – or at least build a different sort of box. As promised, I’m showing how we did it….